Non-isothermal, in situ XRD analysis of dolomite decomposition

✍ Scribed by Philip Engler; Mark W. Santana; Martin L. Mittleman; David Balazs

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 524 KB
• Volume: 140
• Category: Article
• ISSN: 0040-6031
• DOI: 10.1016/0040-6031(89)87285-5

✦ Synopsis

In situ X-ray diffraction (XRD) was used to elucidate the thermal decomposition of dolomite. As opposed to previous efforts that required samples be heated to a specific temperature and held for the duration of an X-ray scan, data was collected at 4O C intervals while continuously

heating the sample at 3O C min -l. Under CO,, dolomite decomposed directly to CaCO,, accompanied by the formation of MgO between 550 and 765" C. No evidence was offered for the formation of either CaO or MgCO, during this first stage. Calcite decomposed to CaO between 900 and 960 o C. Under air, simultaneous formation of CaCO,, CaO and MgO accompanied dolomite decomposition between 700 and 740-750 o C. At the latter temperature, the calcite began to decompose even though a significant amount of dolomite was still present. Simultaneous decomposition of the two carbonates terminated at 780 o C. Also, changes in decomposition rates of the various phases correlated with changes in the rate of weight loss determined by derivative thermogravimetric analysis.